Dynamic conductivity scaling in photoexcited V2O3 thin films

TL;DR

This study uses ultrafast spectroscopy to reveal how the insulator-to-metal transition in V2O3 thin films exhibits a temperature-dependent conductivity scaling, driven by nucleation and growth processes described by the Avrami model.

Contribution

It introduces a simple power-law time scaling for conductivity dynamics in V2O3 during the IMT, linking it to mesoscopic phase growth mechanisms.

Findings

Conductivity increases on a tens of ps timescale during IMT.

A universal power-law scaling (alpha=1/2) describes the dynamics.

Growth of metallic phase follows the Avrami model, indicating self-similar phase evolution.

Abstract

Optical-pump terahertz-probe spectroscopy is used to investigate ultrafast far-infrared conductivity dynamics during the insulator-to-metal transition (IMT) in vanadium sesquioxide (V2O3). The resultant conductivity increase occurs on a tens of ps timescale, exhibiting a strong dependence on the initial temperature and fluence. We have identified a scaling of the conductivity dynamics upon renormalizing the time axis with a simple power law (alpha = 1/2) that depends solely on the initial, final, and conductivity onset temperatures. Qualitative and quantitative considerations indicate that the dynamics arise from nucleation and growth of the metallic phase which can be described by the Avrami model. We show that the temporal scaling arises from spatial scaling of the growth of the metallic volume fraction, highlighting the self-similar nature of the dynamics. Our results illustrate the important role played by mesoscopic effects in phase transition dynamics.